When I was writing the GCaP book, I asked the London tube authority for permission to use their classically dense map. In incredible bout of British bureaucratic officiousness, they offered the tube map at £100 per impression—an offer my publisher was only too keen to refuse. Hence, the map you see on p. 9 of the GCaP book is that of BART, an authority who were pleased to see it further advertised by a taxpayer, as long as it was sourced—an offer my publisher was only too happy abide by.